SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d33508ea7a458fc158cb8d9f410c085cd0a564a254dd3afb0d198c54606499c' 
  AND token = 'xogHPrrTuxCNeOS8chF/S+Y2bj9cCsiYPFx7Sbr6EoY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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