SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '103eb67e30a007495471f6ea7ac6977509e1e6e23880b0394b6eaea4ed5a99e7' 
  AND token = 'o1SYyflzpSF2Ejidj41uAMrqj4EcDAPXWXRp0CqIirs=' 
  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"
    }
  }
}