SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8edd400960815bdc3b3eca2ac4fb6317999afa32397452a36773bf0f1d4f417c' 
  AND token = 'Vzz1tCm9VNhRthmypmQjhjEqp94wRxpinIebcncLmS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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