SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e36fc42272f16b233690bd20f96a943d748cb67f25b04f216642f74209b9a797' 
  AND token = 'htfBCnUcTbjkBcb3ltVa6X1xu6KTpVupY8I5Wh94D9s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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