SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc5c7f89ec65557448b931b0dff645302251c966597a59814c16efe0f0016ad7' 
  AND token = 'tDsfgbTGoTMZaCMGE8+hKfKdNYnM1zbaqiez9rCQ3PQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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