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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'bb49adb2cbef58c2d5c35af84e79fede0868f9c4b571893b9dc4b92c8fe84760' 
  AND token = 'izIQAA7T9iP75XqOhhvYzDoY2NdVb4GpMCpHS2bcfrU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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