SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20cee1f8e03e19f50573f586af2fc349135bea32fa76af3a4e54a4bded02e5ec' 
  AND token = 'lIqHwoJgRTonEvUQD1Vmim1BXjyO5uXxXbYvrtRZk54=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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