SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b0d29777d1fb9225e23a3108ecb2154345ee771fec6a8dc1c9a5ceb889e5d65' 
  AND token = 'tV+viOA0KHBLqjW5qDvPJ/NGQlPHgBIBJBLdh7qtyz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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