SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19ff4ecdd4deb3a506bb2019d84dc2039fc71020ea9064ec0a6da16756ae569e' 
  AND token = '0UR8AqQ1I+d+4+FPLPghizqYuZmtJXfgltjfxkzGe9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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