SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28c16dbcb681d11780f53859aecbf40397b1cc1a0aaa59a0e7676870814e0001' 
  AND token = '6mIxPvzjTuhQUEreI1KdeLEgiZ3uOw3N2jCKXGsawRY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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