SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86f89b700f4db4bd6e397408e5d2b908c285fd7e3e35ce7b18df4777cafa77b1' 
  AND token = 'n4RjCDMpY0kwanlseaWn2AxmKZhadCz2nYHTEPDuZqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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