SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2dc40563ab35bc2fb251ee81738de23dc6689b5da470431375e8517ebd8d48b9' 
  AND token = '+TD0+efygYX1jqVarGAL4JZWW90+nBAVwG38nYPpsCg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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