SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1c8ca0ad2e669452bf7e1d46780f64e8241b34c5c35e17f9e1030af401e637a' 
  AND token = 'W2ASaYzGN1ELuR7Hf5b4Q4NnCtzpNUB5ZrhnFRzoGj0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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