SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27f8dfd99c162c3f85c425cd5b0f0dd4dc4b56edb57d5cc043bd4b8b32745f26' 
  AND token = '3flMm7BMV7K68J9nP9BsVwifsBZa9/+PLr4MOoBIW6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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