SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5d9dddecfbb4900ff4439633857b953d793c6302208ae5b53216a48708baa41' 
  AND token = 'YfQkEky/1h2L+cqYrWXpEoN8kSQ3Lr0QTmKzM9N8gb8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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