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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '1e4f7fdd6b6ec698f6829de399e8640e5e49c945ccc1c3e52ef920f30c52bedf' 
  AND token = 'QYC6GVbyVnx1PsVxZgxtKfIYbV290v3W0r7RV1ttu9g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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