SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '916517270b8eae9641a3a1863152ed1404e9e9162364d12c0286bd7c6798a0e6' 
  AND token = '2RYB/tFdiNqPBU/kfm4s8pBIeMK6UYt5qRVTuQ33e8o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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