SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6559e3f838357729b2d9ee0e157639502e6bca252f1f5ee12bab583ee5ae59e8' 
  AND token = 'DvDdx1DLeSsYndTU5oeps7EXMhCto8DnH86KpMVkCEs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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