SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4de9bd72fbb7f1489fe723f3d45e3af8b28ac32638ff56b394987d8762179be' 
  AND token = 'uMMaLaf0U10miHl1noEHyWhvams5RlpskvIMljbCVNI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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