SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b7531ae5ad8fe4a8979fb94ad95b10d6b8400ba91228a3eb116428dc762b690' 
  AND token = 'pDvClwB6vtr0UFqtDJQOuGhZW58psTT05PgfVRFMH2k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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