SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85506a7401b141fe0f31acf2f9d56d0976dce5018d37f6f6836570e0111c2f88' 
  AND token = 'IyQgBMDZLmMKRzMJ/aBvnw2jqfgO+/Xxw2UcyYPUQb4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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