SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e96885357c79feb27a2a620baea9df4b98614b8bdee25e31ce3840b705cea789' 
  AND token = 'lTpioZdIxl1t8EeBKYDHJuUQSOUJbU+qD6xy2TzYrzg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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