SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae94292427b76fe825cafd9e6ff4639175dac047b776b7a1f04f3c28580a8694' 
  AND token = '/G+/cctSqHLUY8Yojh1Z4ohiZLEJvhAO5lU/lJ/X3Ac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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