SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe7a84923735e704cb12aed78d9ede92bf4780bda818beb110a57c3131f190fd' 
  AND token = '4UtV8VkGYw4gJ9ClDrMqpVmzJkXL2AO8RqgvqPb8Hok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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