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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '245848c4ffe340d1ae0ebc2a97e6b4315d1a8c42aaa2adaafc0f6b20684dbcc4' 
  AND token = 'eY8RdXoJfhvGCCytXXlU4Y94ZtGmXRkjT0c/+df1sW8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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