SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b37c389186a578fef47a873b36f30ba24c1e894b28bb539c05e00f6865e1ca43' 
  AND token = 'qz980FXIwcv3loHiIMZUvSfun4l/buqBUz3YgVVrwoQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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