SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee3de6f2a374a1295425ea34c685600c5e92788d31db77705b04ff50e943dd4c' 
  AND token = 'uKGLhD8Urpef7pmhUMZ3tGowuj6C5GvcQzyZ5/Vu0Ug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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