SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10a7ba3c583c189325fca381e77307f0221abaea562e1cf4d1c8ca1a584faa39' 
  AND token = 'Ou5T9YY3Y4j4/guMBmzCbXIJrH/88Lb3ctCWHciIHBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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