SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffbcf103a3ea56b0f5945fb24f23956c778f5a21add6dbfe0b5d38c91b506d8b' 
  AND token = 'Oqp7XU0tFO2WrBEwr//FgdpR9XnoZ6zqQWMIuTGhVWU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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