SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '522f70efcd79cdebc0f0600fb1165d46f620c9fae606df322269c928f52a4263' 
  AND token = 'PPoL8NfgE+tAeS9UkoYDz9XRRq9h3xiCHOL7cyXGbqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}