SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a03f656194d5ccbd8d7cf0a0497098ed65ce313c8b1c000c7dd8528d482d3a34' 
  AND token = 'yiTVN/czjTscxRtvsCVWIesevQFYVyAVEvXAhxHY8+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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