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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '5bc1b921af8310f941dd5b20aa854cba83cb461d96e24ea5f9e5a34c63e4fded' 
  AND token = 'pe5KB91cmp0y7ATpssL6qc+TP/aS6nTEIf4Au0iSQiI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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