SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2bd9432157c8b18b37631858923c3f5c9b8d1a434b0dae1e3c5a2bfaf9ed75f1' 
  AND token = 'fEq4uZygSSBfvcYuBi0F/5AHcnKxGZJZ5Ww1AisvMNo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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