SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '720688e716974982adf099d111714d134fba69b0aedded1feeddae9570162249' 
  AND token = 'LsW0qgxNT+KQs/x6wFbuFRcfVBn0i0eQ1o6YZPyQXjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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