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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd12bbd7e6a56bb264836f5e5c86c422cf841d6d6ed62fd9fc7956415cb5e0703' 
  AND token = 'jNkaWXU5zFcdlxsQA4gTMwGqcxTtvIjxplgmER6frfE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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