SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '95b85e6ddad0c9fb9856f10aa4b67026b542d6c7e208fdf7123c4bad11249abf' 
  AND token = '/f0w6OTNmMUoqpK1IVJkiCjUHCwYFxRI8AUEflSjJPk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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