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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b43058c84c2ba26b2a01d73d58e0ded2f84471e63bbabcb956ecc00a0455fddc' 
  AND token = 'YO+IYUOlOTaOajArTaEF8kGWObZ0p3LRNkUiWlbptRU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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