SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab5059f62825b54e8a2b86e950148aceb9c1ff2d67c0ae8356996624798bf859' 
  AND token = '00gNzwyoKzMp34oW2jqw7XFwBfRanvcgLH/GisWmRs0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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