SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ae302fcd17f96228e94a3ffee41aaedd74b386b71d537325bf79f15287b05b0' 
  AND token = 'UNjlVwSpSNl+xE/4NcgV1fuhG1U0sM4vSAzCX0va6d4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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