SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91d36742a81fc5a2dc396a3e81435e4f9be7f285d563c4620e4152afebae0379' 
  AND token = 'NLFJfK6t8EWBzHJvaycooJR2fqrtEqIth6Q7D8bwkaE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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