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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c5d921ed3d142f6d0b49ac2e56b52edf0c2e8cc59f78a38b65bb7e6d69df548f' 
  AND token = 'ciORKwGYr//VEPG27QksItvTwOn0dRhZy8oM2mfHkNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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