SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47b5376fe226701dbaff586390038d263aaf7055c21a4ae82acab02bd7bfa527' 
  AND token = 'tgMGg6I9E1z9UB5ZPuZpZFXdajcTn5tWffIMiazT5vw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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