SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56b6e860b7c3f4f851d5149f518ef3065064dda2242ac838da7eb8cc9f28fbd6' 
  AND token = 'tGg06RINcCQgfmoauv/c97vq+XJCwVkC0nLcSjfUPUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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