SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a54d6569cc8ab757d6ff05451967732130495b40303fa9c59d265457656a97d0' 
  AND token = 'vWIpuoqGj6YBxIr5LDTvR7ZyjHAwe26zyeJQYbEpL40=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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