SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ad9d9dc97f846015a83d2ca404ca2314406141bc61ec87378299f88b88e4649' 
  AND token = 'AzGPvAS8ZBG3RC5wpvEjI3kDHQWzezseh2EDvSNkY50=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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