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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c980e7ba0c9199e6e8310ebe6dfac27e52e25c83c91ee209274fe57ac5e50122' 
  AND token = 'x78HicMjGn4ioJ24XQ+WPwMfaM/2eRiD9QdEDc1iZms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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