SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ff1097238ca638e942d44c0369b13e139fa996e4e3b5ee20986bbc1162bea2f' 
  AND token = 'YDSsa18tHJpQnAywvBrCeiidLnqS5yZDs9CGq/0Ent0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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