SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffa27f59b6be42f85953476dab283cadfb68ebd7441f4dfe340928516b3041aa' 
  AND token = 'KOV7JjbUg/eJjqgKfD2rgICHeRUOH0YTOI4jthl+k2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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