SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '709b4b70e484cddbea861d46b43629bd67d561bfc82f99281e5e14026967508e' 
  AND token = 'SSvL9ILP5/SYExRojcV608q6qJ0PtzqMxttdQy0B6MU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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