SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e600fcde532f8539ee96b46217881d1835a016b0c9a93ea5369268875c56e065' 
  AND token = 'vv2ODP3rwBqFhKUAF8kgEHhN4+5XPnpqJBgjOSr2Bis=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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