SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc8299463e61de751837410aad2fa47bc419149e346fb0bf257dc665959138fb' 
  AND token = 'EXViMkBDeK/8v1gUw0+9uMH3ip/fBvEpfJmgRnUr17k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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