SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf74d3fc3da001deb4260fb3afa09e5a3dc1bac0fc450c7b042c626aa4c8e442' 
  AND token = 'CzdA2Wm/y1i9MJtiNRgmI9XhYm10Gi8p6j6SpiFwtmE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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