SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db8f13589d5b44598663e5dc22cdf3a6c3e8889cfed681670ceee4975c281583' 
  AND token = '8xVHeazuMXskf6ipopiMSNhZ9j0aLCq0szNMj6Q1RRE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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