SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5eb1bdccab2451b47d12ac976843f29f3986b2d48be2a229638b8d86519ffd23' 
  AND token = 'BcVYPwXclLuPliPB07QtrnSJCTs6xmsuvVHbB7f/LFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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