SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c28b14bde1542fea8491d482c3aa267636e4c3d6dce7bd5c6ab5f9b3fef2cd19' 
  AND token = 'RKFNXHWaNpYivGR5vT6syMyVOtKaMusTz8TUfOypiFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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