SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e63af60f2e68d7de3f0885a9d2bd6a7d3157f7c9d8fad1cfef3ac9c258f3c5be' 
  AND token = 'MXh9g/Q581HrEViQWX0P0gDor5/Fs+2X6VHwHWjVUp8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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