SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cca548832fd209c5aa152933bd37823d518a477de3a02cd266b2b9df88d04c6' 
  AND token = 'IW4JYm0yCWij7qp+l1u7XfjBaG6VZ5I+RrFHNXVyaV4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00008

JSON explain

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