SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a6f84c23ae47bf8406c31e2fa1d621c66e87e6541213c54b9899ecfa1116e12' 
  AND token = 'PJQpKC9j9XWIF+4pzGkktxzHNUWN//FJvnQQXxNys2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}