SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50f7ff4ca18d2c62fc5b3a8cada7aff3c3263cc4bc3523ff5a456a4a788e4efb' 
  AND token = 'XZinU6+CkkZXx8A39j4mN2U5SfLHNdQcLd55UauQNZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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