SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad5d14351b2b31327fdc24074955376ebffd882ff4ba0b8c8324a33947c65a34' 
  AND token = 'JYMfLAeedwWW30GNxvnbm2+7ex/ZPBvg9MafCezUnzg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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