SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '95b731643181b3b1d106aaa5d6b5edefe060d8e5bc936f6fdf55f53084661252' 
  AND token = 'cV8ckfWRl5vBIZFOwr7g+zdiLsbevMlVMLA07IPmUKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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