SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91d63a770ecdfd663c57973e91012426769d86e3aa864c650840d975445d4fb4' 
  AND token = 'IWFJWsPQs6DIIJk/8PttV1ub35V+Cv7WS4OvRlBvVPw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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