SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ba818fe8594ec916edc4fee34964715adb02e53ff2fe13724e19f26ea290fc6' 
  AND token = 'ROOIymd1CtOlY/2Q+9mmPe4Ysi4sDrO9JylM3ZFqE+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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