SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b17560802a2f9edc83121a73d96b25a7d0a0b0ad1817d9b19330a4849910a3d5' 
  AND token = 'B7ShcgI34Kf/msuE6wXZDL4JPY0GMexpKpLz6dBZxl4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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