SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a21def3e4ac42d1b85a7786382ee2fac5690e39baaaa06c51e415008f87282ea' 
  AND token = 'uCxKUv9cDlnVGjCtIj1Ht8yDDVesd8+Ge1o6wWWEljk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}