SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a29941f8e6a632394a641701c48680d2d3d3f2bdb5d388a9ed7c3d89116bc4b' 
  AND token = 'mwbz9njz+DfcxZ1QnmVvS9rdb/FlQUAZZw+KZmvPBKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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