SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a5c84dfb190f6b70b7e7cbef72fbbcb706a0cad86701453873c20328b5dbbdf' 
  AND token = 'R7tGVgmqiYS3cPFd6v0ogxyBDcfGuM+xPGw6rOj960M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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