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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '5c7362bbbf39f0ba1d8ffe1d0873d7f92478a7f6aa710ae1cf55b0f0b963c961' 
  AND token = 'ZrAXeNuQnPlKScAC9lUkURolLx4OuzvPWCWVTAWPYq4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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