SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67866a953e6e70483afa952072db2c20fb003ede6fd78dc7b42d9889ac318873' 
  AND token = 'Jhv9g+0yn4jZwTptzFKtQNFY8s5kqcPAYj2G06A4slo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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