SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '09e21a89c83d0fb7d4b5cbfad51b4e82a05ead17143d2618e79e7795cf9df53b' 
  AND token = 'B6CQiEN6cbKlqs1S1e/9lJ7wvSAv3HSwhh+WYAYFsnM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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