SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5931b516ceb3272d5ff47ffff2bee3c61dc979c5878ed5f5d397ba548b8761c' 
  AND token = 'ZXLHijkou/DaRhJb56vqTlQaQmq9pnM4BU7H4TUm2Tw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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