SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2edf33c2e393517e6303b8a33c27061d68a284228d3fa2383cfb7cc3a0c31824' 
  AND token = 'JyUm91kUlbVbQY0pOrWym35SQ5Ask5qdjBg6QfEKTgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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