SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a99e23543fc4885c92c4b858bc0b09a07165f0bf9b5c51c7a766e30b3bc9bf5b' 
  AND token = 'yTMJMqqOMAuGskNES4Y6qFF9uUu+G8Lyx40xYAch3Cc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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