SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28adec94fac0aef1a373e38c57586541712e1669b9d81478aed4d3a206f25688' 
  AND token = 'cb6jT8QB0E6k7/7kHeoQH+YguEo0mRt9gDMxvUwcjpE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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