SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c996d711d8fe9592e6f35a154938f86fd12d07453d5adde92fe9c9b1418ee9e' 
  AND token = 'r2UHTkdDcnJYGzyp7gqKMvhUx+2Bud5PtbWCsAyVYAc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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