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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7898ef7ca70fd9362e4c2eedd70f2408c37cc7a3cd8c334245f116fd1c56a6f9' 
  AND token = 'drdQm44blTsUavnVUxWPE1n4iTNp1CPBjrqNpsFOUjU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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