SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e16bf8ec221fedaa3959d8ecc3899f149643cb95b837368496e91996c5f45731' 
  AND token = 'dZFWO5JcJZqkSqoRtdTF7/sUJoSek5sQ6WdL8zaJBZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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