SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4f19e5c1234222a847314693563600d1bce5773bb4082725e876a6e554f1923' 
  AND token = '8aO1He39+YL8urwsvcagWjT4kqerVFMaxqzrT+pnqis=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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