SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0985cccb9ae13c06bf9bf5053497a662997a69f4f4c1876fee9734e1c08f53a3' 
  AND token = 'czudot0lHFB8yDtzSlC8VjgCGdzqZghCgLEENdEWqA0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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