SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bf98aac59cb23ce273db0ac18e002f68106a011fb1700d608cdcc8373ac4b43' 
  AND token = 'LJVX+DoqyaLRvKdxE/dIuzm7uE5qidBsFjnLy37LS1E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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