SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c12b9f66ad7acd6be601d3cc68868261516e33112b6a571870b815206ec92725' 
  AND token = 'x7fzCK/mEz0dHRKVwf+N+NAenyrzknVoT9rwty30cUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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