SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ed98ed902fab3173ca33ab7af1ac7604150bad6eefff6cc538bfca1aa69fd2f' 
  AND token = 'b+T+kTosRQ9vlSha34phJXo/nRc96XQsS7axO0/W2C0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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