SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55d2bb541005b6b5efff863e0fd26a1f471024f35843804e47a851b3a5999d64' 
  AND token = 'dV4nwDTRi7r+oHuFbBrXJhaQqZ8aUaKvOqWu0XVMtrA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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