SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '814c4b67401d22cae19ba44a6a0eb7d9f401407adfc632a902fda16776251288' 
  AND token = 'SbmrIYYzOhmFtICAZ52mEVoLHanp9FnwZjCyvk8MgfA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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