SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2eb5f14f3e5e785719bc1ab8fcfc662fa29c13e5a5fc49fb684d7d675a6b29cf' 
  AND token = 'iNRg+Pugb9tVwk/nhzF43RdwkP3j6OZzh/JQNQI2vIo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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