SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad5affaee56e48478bd14791cfd14e93689e4ae442d0cfd7082374c5e9d4b9b5' 
  AND token = 'AFcgEuRyxnrcFzN0IdIJsnFEWrjBDDnTOWuYIXcd/Mw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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