SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae561eeba47f561d730a84efe94a3aacd33a9a0a26d060f0d4f52c6d81d05271' 
  AND token = 'Le0viQxOZlxr6Fyq1Ch4uQ/G0CkHQHW/7L3+XqljkXg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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