SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ef256db553240f48875a4db990e6616538c89ede81724f69e3e73505996ae88' 
  AND token = 'CwXeWGtlDxSu4cj0RHoua/hoZOCA7TVXtSef+R5scXM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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