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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20c144cc3d88ab0a58873e4ee41fc634d7a6ad51bc42eaf2f3ef855cc27dc17a' 
  AND token = '4Y8bnXadh3EaPWNm5QyQPFa/AjVSbam5f3Dpz3ZpPy8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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