SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7199952bbc649ab04bedef3ba8caa6f2053919f604bb579248a0c56a29152ec' 
  AND token = 'AWhlmBh/o/MG4h8eJdrEKSOEXoyLtyB2C1sxOwkJWYI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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