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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b5177bb1c83b74ecf8c69401ee0e01a65604a361333b3bd96f5c030a95d95ab1' 
  AND token = 'iTN5lBFpynioLf/1AEIVeLN0eZ1fEcIZ7M6sJlHNgoU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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