SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fef15eba3d5b9f97ab670fa8e3d05d989e3fd4297d534292560980e682975f91' 
  AND token = 'hiioFfXlXCnyVf5LGRuKtDmoYGmmAcpxTIzQU6o9bOo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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