SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9cfafa831e9852a530ca0083cdb5b007ba133c4fde6a19fe918e7f5801c6bf9e' 
  AND token = '/YDBtkBRcyiperuFYPWEuCOo1VSOUoW+cKZPW/HEg2k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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