SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08165bb08dc1b3a8c51275264d62af2b225959f0c97d9ce5137ec6460b022df2' 
  AND token = 'a/wBoGPeQ09aKnRl1gtO3RtXCqQWAqoJgqWQw/VePwU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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