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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '6c6c8d65c6022a4a9fa2783dc95446fd4d22ab8eb01f5af920b726556fc98fbb' 
  AND token = 'PdO8NcSI+9rcxdgP3+gUl39lwsMnt9A0RBS9CVbI3i4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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