SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd88ae46ce1753342f9f0d9518d54c9c4ce7a9d54697417370a4bbb3af014ffb9' 
  AND token = 'HgVVuzBrFVKtUSFOjLNRskNJAh3RiCFvmMq6cLMJqgA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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