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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7dd71baa3909ea0d11d6daa81d936b81beb12b47617fbf3bfec795f9e32dfedb' 
  AND token = 'n16FdSbOcO8iqcsDZa1p5+EcVT/0iu7aQbqhz9NXjKQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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