SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3dafc52dc24b70504dede44da2d25c345efad3ba6038f39f4165efffff3bbcd3' 
  AND token = 'v8GyUiMQLKwlDd+asqpfY+nSG3ikVbKbObEm0EC+tkE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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