SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '690d7b4d7961874ba34c178308a2b81524038502299103e39a3fd8718f73b4ba' 
  AND token = 'L/VJgYlv5bJy58ry1gdTUpcF/pIa/6zjZHYv8hCTHww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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