SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc5bd539594d46232b4a52c4f532d9269a23470597cd3516cb49cc2c0d1785de' 
  AND token = '4K4JUTFnAoHk01evDMuWMXATHCgxYYQ/BthaKxNwGRU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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