SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fca9e32cf1bfd56b27478fc4b22805b788b8cff58a13123c56bd656d05b4f5c' 
  AND token = '4OwqGf9geVr5+RursPVMQGLfGLPgHZQ0PCCV9awSJIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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