SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a32cc923e186806226f4bc5656a7476e3b763fae9e6c2234359c5c9763f01da7' 
  AND token = 'sHR8KoMyEFn3P1UGHSaA51wo+VUyqEt5WHqRbcTzqeg=' 
  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"
    }
  }
}