SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61ff49c8761aa386e58e32d8b2903c1b7e9a997e7a510f1e0165375d00d381bd' 
  AND token = 'A9lRPW1XuzyqrSgIhcsYh3yNdGXYlzsru5tmgHfhi9c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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