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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9d37e9435f2452cb8eefc2a56b04b5cd36c1f94d9456e6ccfaf84aba7b6b21d' 
  AND token = 'WWtTSH7d83WMI/FSVfidPuXHANn9qvqVXlGH6zGxr0E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}