SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08ef0334d43e15ac787c0febe26aceee2dc447f54466e4f3edc4c61e4ffb12a4' 
  AND token = 'W/rarJhtIFHMi7zn91IKnyxNwrpdqL/UA1OCAjPrPkw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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