SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc358639ebb6a30934ff24464a0be6d8c91430c32906620ab984dec2528a79cd' 
  AND token = 'NAXzgv8gVF4UU8zTeb5jMwVgmCVZ08hkowvscIEZ8Qg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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