SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e878bcce1ed432e9b9b8caed040977a1d22f99b28e67779aa604034e88b6457' 
  AND token = '6gSUIO5aDoS1BY2yPgx3FOJAaBkK6FhBMlx1OHKubZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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