SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '732e86d6f1ab0846da8c25db752d7762d43fdbafcece816e2779f6c57497b03f' 
  AND token = 'DXlbewu07NcyBkVyd4QZ2JkUWUzBBB6wRpDhf36yvXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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