SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd135eea144f314cb8d8cb58aaf1d2045d21015400523044c3fbc0af9ff798328' 
  AND token = 'yg7hpiT5TdUUA2Qfx3bUQUEfFsV4223ZhHxPSCeTiYQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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