SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d4e4e67a88e27153d5517e0ffe3ae77dffed39fed16411bd1a7d1a4c81aa361' 
  AND token = 'gmm20NuYTWeuiy22L3KDk7dFBMpefQh2C6uKXBjdvbE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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