SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a47026904ff9be99cba7528fa47d47c13dcad877f188c5cf2db2724cc952b76c' 
  AND token = 'V/Z7EHZoQNvnJRth7lVoWXZ3+VHgDYyxpxhnPTi8Vss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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