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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f8bb9323b0376a8b4cd91e79d4dceb12309604d1ba8cc0c5ded1a647cd3cc96' 
  AND token = 'z4G6up1Gp1x+v7CnqtVwTtrRxhoWbVo70H5i1P3VmGI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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