SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de32a17e91dc8cc5885c9f57571fbe4c70e040b83835afc40941fe1d649cb72d' 
  AND token = 't/VpJidlfdMY+nDwvg/HymKv39IQ6vGXnnTeQGkTj2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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